Minnesota HVAC license: there isn't one. What your mechanical bond covers, the city licenses, and your first 30 days

Published November 3, 2026 · Rules checked November 3, 2026

• Free. The printable checklist comes by email.
• Deepsel is our product: free estimate, invoice and scheduling software for contractors (scheduling, quotes, invoicing, card payments). One section, the one before the FAQ, says where it fits.
• Not legal advice. I read every rule here in the statute, the rule, or the Department of Labor and Industry's, the city's or the agency's own page or form on November 3, 2026, and each one is linked in the sources. DLI and your city have the last word.

There is no Minnesota HVAC license. The state doesn't license HVAC companies or HVAC technicians; what it requires instead is a $25,000 mechanical contractor bond, filed with the Department of Labor and Industry (DLI) before you contract any gas, heating, ventilation, cooling, air conditioning, fuel burning or refrigeration work.¹ The licenses come from cities. Minneapolis, St. Paul, Rochester, Bloomington and St. Cloud each license HVAC or heating contractors, mostly with a master's competency card behind the company. Minneapolis wants liability insurance of $100,000/$300,000 bodily injury and $300,000 property damage; St. Paul wants $500,000.^{6, 9, 13, 14} Duluth has no HVAC license, but only a bonded contractor or the homeowner can take out its HVAC permit.¹² In the first 30 days you need the bond on file, workers' comp before your first hire, EPA 608 cards for everyone who touches refrigerant, the city license where you'll work, and a plan for the wiring: unless your tech holds a DLI personal license, the disconnect and reconnect on a furnace or AC swap goes to a licensed electrician.^{16, 20}

The whole 30-day list is further down this page. It also comes as a printable sheet with blanks for your bond number, city license and competency card numbers, policy numbers, EPA 608 card numbers and renewal dates. Get it three ways: make your own copy in Google Docs (lands in your Drive), download the Word version (.docx), or download the PDF. Pick a format, enter your email and I'll send the links.

An owner in a neighboring no-license state described his shop on Reddit like this: "i run a 2man hvac startup company with a partner in the state of Illinois, which does not have a statewide license."³³ Minnesota is the same, with a bond where the license would be. Google's own summary and a couple of guides already say there's no state license, then move on to schools and exams. This page is about the business: what the bond is, which city licenses you need, where the work stops being yours, and what to sort out before the next job. If you hold a plumbing contractor license and "heating" is in your company name, read the section on plumbing and heating firms first.

Minnesota HVAC license requirements: what applies instead

Five layers, and most new companies need two or three of them.

Sources for the table: DLI's bond page, the electrical statute and DLI's HVAC bulletin, the cities' license pages, EPA, and the high pressure piping law.^{1, 6, 9, 13, 14, 15, 16, 20, 26}

The Minnesota mechanical bond: what it is and what it isn't

The statute is two sentences long. "A person contracting to do gas, heating, ventilation, cooling, air conditioning, fuel burning, or refrigeration work must give and maintain bond to the state in the amount of $25,000 for all work entered into within the state."¹ Here's what that means for you, from the statute and DLI's application packet:^{1, 2}

• Who files. The company that signs the contract with the customer. Your employees don't file one.
• How. On DLI's bond form, written by a surety licensed in Minnesota, signed and notarized, with the surety's power of attorney. Filing is $100 and good for two years; renewal is $100, or $150 if it's late. The registration expires the same day the bond does.
• What goes with it. The application, a disclosure of every owner with more than 10% and the key officers, a screen print of your active Secretary of State record, and DLI's workers' compensation certificate of compliance, which DLI wants "by ALL applicants," including those with no employees.
• What it pays for. Customers' losses when you don't follow the State Mechanical Code (Minnesota Rules chapter 1346), up to "the amount needed to correct non-complying work." The surety's total for all claims, "regardless of the number of claims made against the bond or the number of years the bond remains in force," is $25,000.
• It replaces city bonds. The state bond "is in lieu of all other bonds to any political subdivision required for work covered by this section." That's why Minneapolis and St. Paul ask for your state bond, not one of their own.
• What you sign. Employees doing contractor work get W-2s, and "all advertising and business forms will be in the name shown on the bond form." And this line, word for word from the application: "I understand that a Mechanical Bond is NOT a license and that I am prohibited from advertising as a licensed contractor unless I or my company holds a municipal license."

Two other state rules stop at you. The residential building contractor license "does not apply to ... a mechanical contractor," and Minnesota's construction contractor registration doesn't apply to "a person who has given a bond to the state under section 326B.197."³ Customers can look your bond up in DLI's license and registration lookup.³⁵

Plumbing and heating firms: the plumbing license doesn't cover heating

A Minnesota plumbing contractor license lets a company "perform plumbing work in all areas of the state," and plumbing there means water, drain and vent piping, fixtures and sewers, with no gas or heating in it.⁴ So a "Plumbing and Heating" company with only the plumbing license can't contract furnace, boiler, AC or gas work until it files the mechanical bond. DLI enforces this. In March 2026 it ordered a master plumber in Madison Lake to stop "contracting to perform mechanical/HVAC work in the state of Minnesota without the requisite mechanical contractor bond."⁵ St. Paul now wants both bonds from every plumbing and gas fitter business it licenses.¹¹ If "heating" is in your name and you haven't filed, file before the first furnace quote: $100 plus what your surety charges. Our Minnesota plumbing license guide covers the plumbing side.

Your Minnesota HVAC contractor license is a city license: who has to hold what

The state asks nothing of the person. There's no master, qualifier or ownership share behind the bond, and no state rule on how many companies one person can stand behind. The cities ask for a master:

• Minneapolis: the trade license application has a section for the "Qualified master comp card holder" (name, card number, trade), and a Minneapolis master competency card is required for the HVAC Class A, gas fitter, oil burner, refrigeration and steam and hot water licenses.⁶
• St. Paul: each business trade license needs a current St. Paul master certificate of competency in that trade. For warm air and ventilation, a Minneapolis master card also counts.⁹
• Rochester: "Before a contractor can apply for an HVAC Contractor license, they must have at least one licensed master installer employed full-time." The master installer license belongs to the person, is mailed to the master's home, and "is not directly tied to the contractor."¹³

I didn't find a deadline on the cities' pages for replacing a master who leaves, and I couldn't read the Minneapolis or St. Paul ordinances themselves. Ask the licensing office what happens before it happens.

Being someone else's master. Nobody in Minnesota can rent you a state HVAC license, because there isn't one; what gets lent is a city master card. If another company asks to list your card, you'd be the name the city holds to that company's work in that trade, and in Rochester the rule expects you to work there full-time. I found no one-company rule on Minneapolis's or St. Paul's license pages, which isn't the same as there being none. We cover the pay and the risk in a separate article.

Minneapolis, St. Paul, Duluth and Rochester: the city licenses on top of the bond

DLI says it plainly: "In addition to filing a bond with DLI, mechanical contractors must comply with local licensing requirements."¹ Here's what Minneapolis, St. Paul, Duluth and Rochester want, plus Bloomington and St. Cloud, which license too.

• Minneapolis. HVAC Class A covers a contractor who "installs, fixes, and cleans air handling equipment and air distribution systems for heating, ventilation, or air conditioning." Class B (duct cleaner) only cleans. Gas fitter covers "fuel gas burning equipment and systems," refrigeration systems installer covers "refrigeration equipment and systems," and there are oil burner and steam and hot water licenses. Each of those takes the state $25,000 bond, a Minneapolis master competency card (not Class B), and a liability certificate of $100,000/$300,000 bodily injury and $300,000 property damage, with the City of Minneapolis as certificate holder and additional insured and your legal name matching word for word. The business must have a Minnesota address. Licenses expire December 1 and run no longer than a year.⁶ Start at the city's trade licenses page.
• St. Paul. Separate business trade licenses: warm air ("a heating appliance (furnace) and ducts"), ventilation, gas burner, oil burner, refrigeration ("central air conditioners, chillers, heat pumps, walk-in coolers"...) and steam fitting (boilers, hydronic piping, in-floor heat). Each needs the master card for that trade, a certificate of insurance with a $500,000 combined single limit (or $500,000 bodily injury and $200,000 property damage) and 30 days' notice of cancellation, the $25,000 mechanical bond on file at DLI, proof of workers' comp, and $188 a year. All expire December 1. Competency cards are $24 per trade and also expire December 1.⁹ By the city's own definitions, a gas furnace with central AC in St. Paul touches three licenses: warm air, gas burner and refrigeration. Start at the city's trade licensing page.
• Duluth. No city HVAC license. "The HVAC permit must be taken out on ePlace by a mechanical contractor bonded by the Minnesota Department of Labor and Industry (DLI)," or by the owner of a one- or two-family home.¹² Duluth groups gas piping permits with plumbing; see the gas section below.
• Rochester. An HVAC contractor license ($125) covering warm air and hot water heating, chilled water, ventilation, refrigeration, "gas burners and gas piping," oil burners, fireplaces and more, with at least one licensed master installer employed full-time. The master installer license is $60 and needs a Rochester certificate of competency, $25 per area: warm air heating and ventilation; hot water and low pressure steam heating; refrigeration and air cooling; gas piping; and factory-built fireplaces, stoves and chimneys. The city's page says its trade and contractor licenses expire December 31.¹³ Start at Rochester's trade licenses page.
• Bloomington and St. Cloud. Bloomington's contractor license needs the mechanical bond on file plus a Minneapolis or St. Paul competency card or a pass on its own open-book test ($35), with categories for Gas Installer Class A ("Gas lines to furnaces, boilers, make-up air and rooftop units"), HVAC, hot water and steam, oil burner and commercial refrigeration. St. Cloud's heating contractor license needs a St. Cloud Master A or B Mechanical Installer certificate, a copy of your DLI bond certificate, and liability insurance of $100,000/$500,000/$250,000 naming the city.¹⁴

Those are the six cities I read. Other towns may run their own registration: the bond application itself warns that "I may be required by a municipality to obtain a local registration prior to becoming eligible to obtain a building permit."² Call the building department before your first job in a new town.

What the bond lets you take on, and where it stops

The bond covers contracting the HVAC work itself, residential or commercial, with no dollar limit and no split between heating and cooling.¹ The edges are other licenses.

• Gas piping. Statewide, gas isn't plumbing, so a bonded mechanical contractor contracts it.^{1, 4} Cities narrow that. Minneapolis's mechanical permit form says "All gas piping and gas venting for heating appliances must be done by a licensed gas installer and requires a separate permit," and the city's licenses that cover gas are gas fitter and plumbing.^{6, 8} St. Paul licenses gas burner work and plumbing/gasfitter work, which includes gas piping.^{9, 11} Bloomington and Rochester test gas piping as its own competency.^{13, 14} Duluth needs a gas piping permit for new or replacement gas lines to furnaces, fireplaces and water heaters, but not "when replacing appliances and equipment that has an existing shutoff"; its page says plumbing permits are taken out by a DLI-licensed plumbing contractor or the homeowner, so ask the city who may pull a gas line permit before your first one there.¹²
• The circuit and disconnect. Setting a furnace, condenser or air handler isn't electrical work, but "The installation of electrical wiring to the unit is covered" by the Electrical Act. A new circuit or disconnect for a condenser, mini-split or new furnace location goes to a licensed electrical contractor with its own electrical permit.¹⁵ Our Minnesota electrical license guide covers who inspects that permit in each city: the state in Minneapolis and Duluth, the city in St. Paul, Rochester, Bloomington and St. Cloud.¹⁸
• Replacing a furnace or AC on the existing circuit. DLI's bulletin: an HVAC contractor can do it without an electrician, disconnecting and reconnecting "the existing branch circuit connection without modifying the circuit," if the work is done by its employee who either finished an approved Minnesota HVAC apprenticeship or "holds any class of personal license issued by" DLI. Then the footnote that matters: "No DLI-approved HVAC apprenticeship program exists at this time." So it rests on the personal license. "If the above conditions are not met, or if any modification to the existing branch circuit is needed, a licensed electrical contractor must be hired."¹⁶ The statute says any class of personal license issued by the commissioner, not only an electrical one. I found no DLI list of which licenses it accepts here, so confirm yours with DLI before you rely on it.
• Thermostat and control wiring. The same exemption covers "associated devices, controls, and wiring including wiring in or on the equipment" when that qualified employee does it.¹⁵ Without it, DLI treats HVAC low-voltage control wiring as technology system work: its technology permit form lists "Class 2 Remote Control (HVAC)," and its chart says class 2 control circuits that control line-voltage equipment in a home need a registered or licensed person working for an electrical or technology systems contractor, and an inspection.¹⁷ My reading: a qualified tech swapping a thermostat or rewiring controls on a unit you're servicing is inside the exemption; an unlicensed tech running new thermostat cable on a new system is the case to ask DLI about first.
• Electric water heaters. Not yours either way. DLI: "A licensed electrical contractor must be hired to replace the electric water heater."¹⁶ The heater itself is plumbing.
• Refrigeration. Inside the bond, statewide, from a walk-in cooler to a supermarket rack. Minneapolis wants the refrigeration systems installer license and St. Paul the refrigeration license, which in St. Paul also covers every central AC and heat pump.^{6, 9} Ammonia piping is "high pressure piping" in Minnesota, and so is hot water heating over 30 psi and 250°F or high pressure steam: that work needs DLI's high pressure piping contractor license, which takes a licensed master pipefitter, and a permit before you start.²⁶
• Boilers and hydronic heat. Inside the bond. A home boiler needs no state boiler permit and no boiler license: the boiler law excludes boilers in buildings used only as residences for five families or fewer, and DLI's installation permit starts above 750,000 BTU input for hot water heating boilers, 200,000 for hot water supply boilers and 100,000 for steam.²⁵ Minneapolis (steam and hot water) and St. Paul (steam fitting) license the trade.^{6, 9}
• Oil burners. Inside the bond as "fuel burning" work. Minneapolis licenses oil burner installers (oil with a flash point of 100°F or higher and a tank over 10 gallons, plus the tanks, piping, pumps and controls), and St. Paul has an oil burner license.^{6, 9}
• Ductwork and mini-splits. Both are yours under the bond. Minneapolis's HVAC Class A covers "air distribution systems," St. Paul's warm air license covers ducts, and Duluth requires an HVAC permit for ductwork.^{6, 9, 12} A mini-split's line set and charge are yours; its new circuit is the electrician's.¹⁵
• Plumbing: fill lines, humidifier water, condensate. Plumbing in Minnesota includes all potable water distribution piping and "all drainage and vent pipes," and contracting it takes a plumbing contractor license.⁴ By my reading, a new water line to a boiler fill or a humidifier, or a new drain or standpipe for condensate, is plumbing, while running the condensate line to an existing drain or pump is part of your install. DLI does enforce this against HVAC firms: in October 2026 it fined a North Mankato heating and air company $7,000, $5,000 of it stayed, for doing plumbing work without the license.⁵
• Building work. Your HVAC work is exempt from the residential license. Sell framing, drywall or other trades on the same job and two or more of those skills need a residential building contractor or remodeler license.³ The Minnesota residential license guide covers it.

Federal rules every HVAC company meets: EPA 608, A2L refrigerants and lead

EPA Section 608. Technicians "who maintain, service, repair, or dispose of equipment that could release refrigerants into the atmosphere must be certified," by type (I small appliances, II high pressure, III low pressure, or Universal). The cards don't expire. Apprentices are exempt only while "closely and continually supervised by a certified technician." The supply house has to check too: "Any person servicing, installing or disposing of stationary appliances (except the disposal of small appliances) must be a section 608 certified technician," and the seller must verify the buyer is, or employs, one.²⁰ Keep a copy of every tech's card on file and give the supply house your list.

A2L refrigerants (R-454B, R-32). Minnesota's code is still the 2020 Minnesota Mechanical and Fuel Gas Code, built on the 2018 International Mechanical Code, in effect since April 6, 2020, and rule chapter 1346 has no Minnesota amendment of its own on A2L refrigerants (I searched it). DLI is working on the 2024 IMC and IFGC; its advisory group accepted the 2024 model language on "Group A2L refrigerant piping testing" in December 2024, but the rulemaking's hearing and effective dates were still "To be determined" when I read the docket.¹⁹ Until then, follow the equipment's installation instructions and ask the city's mechanical inspector what they want to see. On the federal side, EPA's rule of May 26, 2026 "allows the inventory of residential and light commercial air conditioning and heat pump equipment that was manufactured in the United States or imported into the United States before January 1, 2025, to continue to be installed."²¹

Lead-safe work (RRP). EPA runs the renovation rule in Minnesota. Cutting into more than 6 square feet of painted surface per room in a pre-1978 home (20 outside), say for a new duct chase or a return grille, needs an EPA-certified firm and a certified renovator, sole proprietors included. Penalties run up to $49,772 per violation.²²

Helpers, apprentices and who can work alone

With no state HVAC license there's no state helper ratio and no state registration for HVAC helpers. The limits come from elsewhere:

• Refrigerant: a helper without a 608 card works only under close and continual supervision of a certified tech.²⁰
• Wiring: only an employee with a DLI personal license may disconnect and reconnect the circuit on a change-out.¹⁶
• Minneapolis: masters and journeymen in fuel gas, refrigeration, warm air and ventilation, and steam and hot water "need the card in order to perform work in Minneapolis." The exam needs four years of work experience and, for mechanical trades, 576 hours of trade-related education (production work doesn't count). The card is $30 per trade after you pass.⁷
• St. Paul: "Every trade worker who works on any building or structure in Saint Paul must be currently registered" before doing any work, every year, in refrigeration, steamfitting, warm air heating and ventilation and other trades: $37 for the first four years in the trade, $70 for years five and six, $59 after that.⁹
• Registered apprentices: the state apprenticeship law sets one apprentice for the first journeyworker on site plus one for every three more, unless a union agreement or an approved program says otherwise.³²
• Pay: the bond application has you certify that employees doing contractor work are paid on W-2s.²

Permits and inspections for HVAC work in Minnesota

Minnesota's permit rule says whoever intends to "install, enlarge, alter, repair, remove, convert, or replace any gas, mechanical, electrical, plumbing system" must "first make application to the building official and obtain the required permit." The mechanical exemptions are short: portable heating, cooling and ventilation units, "replacement of any part that does not alter approval of equipment or make the equipment unsafe," piping inside the equipment, and self-contained refrigeration with ten pounds of refrigerant or less or a motor of one horsepower or less.²³ A tune-up or a capacitor needs no permit. A new furnace or condenser does.

Who inspects. The State Building Code, mechanical code included, "applies statewide," and cities that had adopted it by 2008 must keep enforcing it.²⁴ DLI's Local Code Lookup shows all 81 of the larger cities our plumbing research checked have adopted it, Minneapolis, St. Paul, Rochester and Duluth included, so the city issues the mechanical permit and inspects.²⁴ The electrical permit for any new circuit is separate.

The like-for-like change-out.

• Minneapolis: an AC or heat pump replacement is a Level 1 residential mechanical permit, a furnace or boiler change-out Level 2, and a full system replacement Level 3. Concealed work needs a rough-in inspection, and for new gas, oil or fuel burning equipment the city wants a heat test record (ORSAT) "including installers name and competency card number," a heat loss calculation and the appliance manual.⁸ Start at the city's mechanical permits page.
• St. Paul: a refrigeration permit for "central air conditioners ... heat pumps," a gas burner permit for gas furnaces, boilers and space heaters, and warm air permits for ductwork. Furnace replacements "require whole house heat loss calculations," and the city's sheet quotes the energy code: size equipment by ACCA Manual S, with heating oversized no more than 40% and cooling no more than 15%.¹⁰ Start at the city's mechanical permits page.
• Duluth: HVAC permits for furnaces, boilers, space heaters, gas fireplaces, ductwork, radiant and baseboard heat, air exchangers, AC and refrigeration equipment, pulled on ePlace by a DLI-bonded contractor. Commercial jobs need engineered plans except "simple like-for-like equipment replacements (must be under 400,000 BTUs)."¹² Start at Duluth's HVAC page.

The homeowner exemption. It covers the owner's own hands, not yours. Minneapolis lets an owner who owns and occupies a single-family home take out the mechanical permit, but gas piping and venting still need a licensed gas installer. St. Paul's homeowner affidavit says the owner "must physically perform" the work and it's "unlawful for homeowners to perform" it on rented property. Duluth puts it this way: "A handyman, or 'my neighbor's buddy,' is not legally able to pull a permit to perform work on behalf of a homeowner unless they are a licensed contractor."^{8, 10, 12} If you do the work, you pull the permit.

The gas utility. CenterPoint Energy: "A houseline pressure test is required before we can set your new gas meter," and the local inspector tells the utility when it passes. Xcel Energy: new Minnesota gas meters "may be locked at the time they are installed unless an approved inspection tag has been provided," only Xcel may operate the meter's inlet valve, and "authorized heating contractors or gas inspectors may operate the gas meter outlet valve" after the installation and inspection requirements are met.²⁷ On new construction, put the inspection ahead of the lighting date on your schedule.

Can I take this job? A table for Minnesota HVAC contractors

Your first 30 days: the checklist

The same list as the printable sheet. Week 1 is the company and the bond; the rest can run alongside your first jobs.

A. Company and the bond

• Secretary of State filing active, with the exact name you'll use on the bond, insurance, trucks and ads. An LLC is $155 online; an assumed name is $50 online.³⁰
• Federal EIN, Minnesota Tax ID (needed before you withhold from a paycheck) and an unemployment insurance number once you have employees; the bond application asks for all three.^{2, 30}
• $25,000 mechanical contractor bond on DLI's form, signed, notarized, with the surety's power of attorney, filed with the $100 fee, the owner disclosure and the workers' comp certificate. DLI's packet has every form.²
• Look the bond up in DLI's lookup once it's filed, and write down the expiry: the registration ends the day the bond does.^{2, 35}
• Plumbing and heating firms: file the bond before you quote any heating or gas work.⁵

B. Insurance and workers' comp

• No state liability minimum for HVAC. Buy to the highest city you'll work in: Minneapolis $100,000/$300,000 bodily injury and $300,000 property damage, city named as certificate holder and additional insured; St. Paul $500,000 combined single limit, DSI as certificate holder, 30 days' notice of cancellation; St. Cloud $100,000/$500,000/$250,000.^{6, 9, 14}
• Workers' comp before the first employee starts. Without it, DLI can order up to $1,000 per employee per week, and a willful failure is a gross misdemeanor.²⁹

C. City licenses

• Minneapolis: HVAC Class A, plus gas fitter, refrigeration, oil burner or steam and hot water for that work, each with a master card holder named. Expires December 1.⁶
• St. Paul: a trade license per trade ($188 each), the master card per trade, and trade worker registration for every worker. Expires December 1.⁹
• Rochester: HVAC contractor license with a full-time master installer. Bloomington and St. Cloud: their contractor licenses. Duluth: a ePlace account for HVAC permits.^{12, 13, 14}
• Any other town: call the building department about local registration before the first job.²

D. People, refrigerant and wiring

• EPA 608 card number on file for everyone who touches refrigerant, and your list given to each supply house.²⁰
• Decide who does the circuit on change-outs: a tech with a DLI personal license, or an electrical contractor you've lined up.¹⁶
• Minneapolis competency cards for masters and journeymen; St. Paul worker registrations.^{7, 9}
• Employees on W-2.²

E. Permits, name and contracts

• Shop rule: the permit goes in before the work starts, change-outs included. Put it on the quote as its own line.²³
• For each furnace job: heat loss calculation and sizing within Manual S limits (St. Paul), heat test record with the installer's card number (Minneapolis). Our HVAC installation checklist has a commissioning sheet for the rest.^{8, 10}
• Ads and business forms (quotes, invoices, and I'd count truck lettering) in the exact name on the bond: the bond application has you certify it. Don't call yourself "licensed" unless you hold a city license. I found no state rule on vehicle lettering for mechanical contractors.² Our HVAC invoice template has a line for your bond and city license numbers.
• A residential contract with the scope and price in writing, the mechanic's lien notice if you'll buy materials or hire subs for the job (without it you lose the lien), and the statutory warranty, which is 2 years for heating or cooling installed as a home improvement.³¹ The Minnesota residential construction contract template has the wording.
• Subs lined up: a licensed electrical contractor, a licensed plumbing contractor, and a gas installer in Minneapolis if you don't hold the gas license.^{4, 8, 15}
• Pre-1978 homes: EPA RRP firm certification and a certified renovator if you'll cut painted walls or ceilings.²²

F. Renewals

• Mechanical bond filing: every two years, $100, or $150 late.²
• Minneapolis licenses, St. Paul trade licenses and St. Paul competency cards: December 1 every year. Rochester: December 31. St. Paul worker registrations: one year from issue.^{6, 9, 13}
• Insurance and workers' comp renewal dates in the calendar, with the new certificate sent to each city.^{6, 9}

What happens if you cross the line

• Contracting HVAC work without the bond. The bond requirement is part of chapter 326B, so DLI's penalty powers apply: up to $10,000 per violation, a stop work order with $5,000 a day for working through it, and it's a misdemeanor (up to 90 days and $1,000).²⁸ DLI's 2026 enforcement list so far has four orders, by my count, that include stopping "contracting to perform mechanical/HVAC work" without the bond: a master plumber in Madison Lake ($5,000, stayed), two Minneapolis property maintenance firms ($20,000 each, $10,000 stayed) and a Minneapolis and Bloomington remodeler ($10,000), each alongside other violations.⁵
• Electrical or plumbing work without the license. The same DLI powers. The North Mankato heating and air company above paid for plumbing it wasn't licensed to do.^{5, 28}
• No city license or no permit. Each city sets its own penalties; I didn't read them. Minneapolis's permit application has the applicant certify that "unlicensed persons shall not be hired to perform work that requires a license or certificate of competency."⁸ The permit rule is part of the State Building Code either way.²³
• No workers' comp. Up to $1,000 per employee per week; a willful failure is a gross misdemeanor.²⁹
• Getting paid. I found nothing in the bond statute that voids your contract or your mechanic's lien if you didn't file. The lien rule for unlicensed contractors in 326B.845 is written for the residential building licenses, which don't apply to mechanical contractors.^{3, 34} I didn't research case law, so don't count on collecting for work you weren't bonded or licensed for; ask a lawyer.
• Insurance. I found no Minnesota rule on whether a liability policy pays for work outside your city license. Ask your agent in writing what the policy excludes, gas and electrical work in particular.

More for new HVAC contractors

• HVAC pricing guide: what to charge for a service call, your labor rate and the first jobs, with a free rate sheet.
• HVAC tune-up checklist: the visit in order, the target readings and what to charge, with a free report card.
• Opening a supply house account: what to bring, cash or credit, and how dealer programs work, with a free checklist.
• Quoting your first system replacement: the price, the scope and what the quote must include, with a free proposal template.
• Starting an HVAC business while still employed: side work, your boss's customers, non-competes and when to go.
• Register every install: maker deadlines, your labor warranty and what a callback costs, with a free close-out sheet.
• Your first slow season: the customer list and the one reminder that fills a calendar, with a free log.

Where Deepsel fits

Deepsel won't file your bond, pull permits, book the inspector or remind you when the bond, city licenses or competency cards renew. Here's what it does do. You write one shop-wide terms text that's copied onto every quote the customer sees and signs on screen, and one invoice footer that goes on every invoice: put your company name as bonded, the bond number, your city license numbers and your warranty line there once. Each job has internal notes and internal file attachments that customers never see, which is a place for the permit number, the heat loss calculation and the inspection report, and each visit holds photos. Checklist templates you build (a change-out list with the permit, the heat loss, the gas test and the 608 card check, say) can be added to a quote and ticked off by the office and the techs. A customer's equipment record holds the unit's type, brand, model, serial number, year, filter size, tonnage, refrigerant or AFUE, location and a nameplate photo. The Free plan covers 30 estimates and 30 invoices a month for your whole team; Pro is $29 a month for unlimited estimates and invoices. Details are on the pricing page.

Frequently asked questions

Does Minnesota have a state HVAC license?

No. Minnesota doesn't license HVAC contractors or HVAC technicians at the state level. In DLI's words, "there is no state license required for mechanical contractors," and "Minnesota also has no state license requirement for individual employees of mechanical contractors." What the state requires is a $25,000 mechanical contractor bond, filed with the Department of Labor and Industry before a company contracts to do gas, heating, ventilation, cooling, air conditioning, fuel burning or refrigeration work. Cities license on top: Minneapolis, St. Paul, Rochester, Bloomington and St. Cloud each have an HVAC or heating contractor license, usually with a master's competency card behind it. Federal EPA Section 608 certification still applies to anyone who handles refrigerant.

What are the Minnesota HVAC license requirements for a new company?

Statewide: register the business with the Secretary of State, file the $25,000 mechanical contractor bond with DLI on DLI's own form (a $100 filing, good for two years), and send DLI's workers' compensation certificate of compliance with it. There is no exam, no qualifier and no state insurance minimum. Then the city: Minneapolis wants a city license with a Minneapolis master competency card and liability insurance of $100,000/$300,000 bodily injury and $300,000 property damage; St. Paul wants a trade license per trade at $188 a year with a St. Paul (or, for warm air, Minneapolis) master card and $500,000 of insurance; Rochester wants an HVAC contractor license with a full-time licensed master installer. Everyone who handles refrigerant needs EPA 608 certification.

How much does it cost to become an HVAC contractor in Minnesota?

The state part is small: $100 to file the mechanical bond with DLI for two years ($100 to renew, $150 if late), plus whatever your surety charges for the $25,000 bond, plus $155 to form an LLC online with the Secretary of State. City licenses add the rest. St. Paul charges $188 a year per trade license, $24 per competency card and $37 a year to register each new trade worker. Rochester charges $125 for the HVAC contractor license, $60 for the master installer license and $25 per competency area. Minneapolis charges $30 per trade for a competency card after you pass the exam, and its license fees are on the city's fee schedule. Bloomington's mechanical test is $35.

Can an HVAC contractor do the electrical on a furnace or AC replacement in Minnesota?

Only the disconnect and reconnect of the existing circuit, and only with the right person. DLI says an HVAC contractor can replace a furnace or air conditioner without hiring an electrician, disconnecting and reconnecting the existing branch circuit without modifying it, if the work is done by an employee of the HVAC contractor who either finished a state-approved HVAC apprenticeship or holds any class of personal license issued by DLI. DLI adds that no approved HVAC apprenticeship program exists, so in practice it's the personal license. Any new circuit, a new disconnect or a change to the existing circuit needs a licensed electrical contractor, and so does replacing an electric water heater.

Who can install gas piping in Minnesota?

Statewide, gas piping isn't plumbing: contracting gas work takes the $25,000 mechanical contractor bond. Cities narrow it. In Minneapolis, gas piping and gas venting for heating appliances must be done by a licensed gas installer on a separate permit, and the city's gas fitter and plumbing licenses are the ones that cover gas. St. Paul licenses gas burner and plumbing/gasfitter businesses, and its plumbing/gasfitter license needs both the plumbing and mechanical bonds. Bloomington has a Gas Installer Class A competency for gas lines to furnaces, boilers, make-up air and rooftop units, and Rochester tests gas piping as its own area. Duluth handles gas piping permits with its plumbing permits.

Do I need a residential building contractor license to do HVAC in Minnesota?

No. The residential building contractor and remodeler license doesn't apply to a mechanical contractor, and a company that has filed the mechanical bond is exempt from Minnesota's construction contractor registration too. The exemption covers the HVAC work. If you also sell two or more other construction skills on a job, such as framing, drywall or finish carpentry around a new duct chase, that work needs a residential building contractor or remodeler license, or a licensed contractor to do it.

Do I need a boiler license to install a boiler in Minnesota?

Not for a home. Minnesota's boiler license is an operator's license: it's required "to operate a boiler, steam engine, or steam turbine." The boiler law doesn't apply to boilers in buildings used only as residences for five families or fewer, or to hot water heating boilers up to 750,000 BTU per hour input. DLI's boiler installation permit applies only above set inputs: over 100,000 BTU for steam boilers, over 200,000 BTU for hot water supply boilers, and over 750,000 BTU for hot water heating boilers. Contracting the boiler work still needs the mechanical bond, and Minneapolis and St. Paul license steam and hot water work separately.

What mechanical code does Minnesota use?

The 2020 Minnesota Mechanical and Fuel Gas Code, Minnesota Rules chapter 1346, in effect since April 6, 2020. It adopts chapters 2 to 15 of the 2018 International Mechanical Code and chapters 2 to 8 of the 2018 International Fuel Gas Code, with Minnesota amendments, plus ASHRAE 62.2 for home ventilation. DLI links a free online copy. DLI is working on a move to the 2024 IMC and IFGC: its request for comments was published February 2, 2026, and the hearing and effective dates were still "to be determined" on November 3, 2026.

What is a competency card in Minneapolis?

A personal certificate showing a tradesperson passed the city's exam. Masters and journeymen in fuel gas fitting, refrigeration, warm air and ventilation, steam and hot water, and plumbing with gas need one to work in Minneapolis, and the city's HVAC Class A, gas fitter, refrigeration, oil burner and steam and hot water business licenses each need a master card holder. You apply with at least four years of work experience and, for the mechanical trades, at least 576 hours of trade-related education; after passing you pay $30 per trade. Minneapolis and St. Paul honor each other's cards through reciprocity.

Sources

1. Minnesota Statutes 326B.197 ("A person contracting to do gas, heating, ventilation, cooling, air conditioning, fuel burning, or refrigeration work must give and maintain bond to the state in the amount of $25,000 for all work entered into within the state"; for the benefit of persons suffering loss from "the contractor's failure to comply with the requirements of the State Mechanical Code"; "in lieu of all other bonds to any political subdivision required for work covered by this section"; biennial filing fee of $100), revisor.mn.gov; DLI, "Mechanical contractor bond requirements" ("While there is no state license required for mechanical contractors, businesses must file a $25,000 mechanical contractor bond with DLI"; "The fee for filing a bond with DLI is $100 and the filing is valid for two years"; "In addition to filing a bond with DLI, mechanical contractors must comply with local licensing requirements"; "Minnesota also has no state license requirement for individual employees of mechanical contractors. However, cities may require licensure or a competency card"), dli.mn.gov; both read November 3, 2026.
2. DLI, Mechanical Contractor business registration packet (application and bond form dated 8.1.2024): fees $100 new, $100 renewal, $150 renewal with late fee; disclosure of owners "owning more than 10 percent"; workers' compensation certificate of compliance "must be completed and submitted with this application by ALL applicants"; FEIN, Minnesota tax ID and unemployment insurance number; declarations that employee compensation "will be reported on an Internal Revenue Service W-2 form", "All advertising and business forms will be in the name shown on the bond form", the registration "expires the same day that the bond expires", "I may be required by a municipality to obtain a local registration prior to becoming eligible to obtain a building permit", and "a Mechanical Bond is NOT a license and that I am prohibited from advertising as a licensed contractor unless I or my company holds a municipal license"; bond: comply with "the Minnesota State Mechanical Code (Minnesota Rules, Chapter 1346)", pay "the amount needed to correct non-complying work", aggregate liability "regardless of the number of claims made against the bond or the number of years the bond remains in force" not to exceed $25,000. dli.mn.gov (PDF), read November 3, 2026.
3. Minnesota Statutes 326B.805 subd. 6 (the residential license requirement "does not apply to: ... (6) a mechanical contractor"; two or more special skills need a license), revisor.mn.gov; 326B.802 subd. 8 ("Mechanical contractor" means a person "in the business of erection, installation, alteration, repair, relocation, replacement, addition to, use, or maintenance of any heating, ventilating, cooling, process piping, plumbing, fire protection, or refrigeration systems"), revisor.mn.gov; 326B.701 subd. 2(b)(2) (contractor registration does not apply to "a person who has given a bond to the state under section 326B.197 or 326B.46"), revisor.mn.gov; all read November 3, 2026.
4. Minnesota Statutes 326B.46 subd. 1b (a plumbing contractor license "authorizes the contractor to offer to perform and, through licensed and registered individuals, to perform plumbing work in all areas of the state"), revisor.mn.gov; DLI, "Plumbing contractor licensing basics" (plumbing systems include "all potable water, building supply, and distribution pipes; all plumbing fixtures and traps; all drainage and vent pipes; and all building drains and building sewers"), dli.mn.gov; both read November 3, 2026 (from Deepsel's Minnesota plumbing license research).
5. DLI, "Plumbing Enforcement Actions, 2026 Year to Date": Madison Lake master plumber, March 30, 2026, ordered to "cease and desist from contracting to perform mechanical/HVAC work in the state of Minnesota without the requisite mechanical contractor bond; $5,000 monetary penalty, stayed with conditions"; two Minneapolis property maintenance companies, October 23, 2026, each "$20,000 monetary penalty, $10,000 stayed with conditions", including mechanical/HVAC work "without the requisite contractor bond"; a Minneapolis and Bloomington remodeler, May 14, 2026, "contracting to perform mechanical work ... without the requisite licensure and bonding; $10,000 monetary penalty"; a North Mankato heating and air conditioning company, October 21, 2026, plumbing work without licensure, "$7,000 monetary penalty, $5,000 stayed with conditions" (counts are mine; names kept off this page). dli.mn.gov (PDF), read November 3, 2026.
6. City of Minneapolis, "Trade licenses", "HVAC Class A or B license" ("HVAC Class A and B requires a State of MN $25,000 bond"), "Gas fitter license", "Oil burner installer license", "Refrigerator systems installer license" and "Steam and hot water systems installer license" (pages last updated September 3, 2026), minneapolismn.gov; "License Application: Trades" (last updated 7/30/26): HVAC A "installs, fixes, and cleans air handling equipment and air distribution systems for heating, ventilation, or air conditioning"; Duct Cleaner (HVAC B); Gas Fitter "installs and fixes fuel gas burning equipment and systems"; Plumber covers "fuel gas piping, combustion air piping, fuel gas venting or gas burner equipment"; for HVAC A, gas fitter, oil burner, refrigeration and steam and hot water: insurance "$100,000/$300,000 for bodily injury and $300,000 for property damage", "a $25,000 State of Minnesota bond", "Minneapolis Master Competency Card is required"; "Qualified master comp card holder"; "your business must be located in Minnesota"; expiration December 1; "No license will be issued for longer than one year"; insurance certificate with "City of Minneapolis as certificate holder and additional insured" and the legal name matching "exactly (word for word)". minneapolismn.gov (PDF); all read November 3, 2026.
7. City of Minneapolis, "Competency cards" ("Masters and journeymen in the following trades need the card in order to perform work in Minneapolis. Fuel gas fitter, Plumber/gas specific, Refrigeration, Warm air/ventilation, Steam and hot water"; "a minimum of four years work experience"; mechanical trades "at least 576 hours of trade-related education"; "Regular job duties or production work do not count"; "$30 per trade"; reciprocity with St. Paul; last updated September 4, 2026). minneapolismn.gov, read November 3, 2026.
8. City of Minneapolis, "Mechanical permits" ("A mechanical permit is required to legally perform HVAC work for any construction project"; last updated February 27, 2026), minneapolismn.gov; "Mechanical Permit Application" (updated 6/3/24: Level 1 "A/C or Heat pump add on or replacement", Level 2 "Change out boiler" and "Change out furnace", Level 3 "Remove existing heat/cool/vent system and install a new system"; plans for new commercial work, "Equipment Replacement - upon request"; homeowner exemption in MCO 85.80 for owners who "own and currently occupy" a single-family dwelling; "All gas piping and gas venting for heating appliances must be done by a licensed gas installer and requires a separate permit"; certification that "unlicensed persons shall not be hired to perform work that requires a license or certificate of competency"), minneapolismn.gov (PDF); Bulletin 2016-01, "Residential Mechanical Permits and Inspections" (rough-in inspection on concealed work; "A completed heat test record (ORSAT test) including installers name and competency card number", "Heat loss calculation", "The appliance operating manual"), minneapolismn.gov (PDF); "Construction work exempt from permit" (last updated March 31, 2026), minneapolismn.gov; all read November 3, 2026.
9. City of Saint Paul, Department of Safety and Inspections: "Warm Air/Ventilation Business Trade License" (warm air covers "a heating appliance (furnace) and ducts"; "A current City of Saint Paul Certificate of Competency (Master Warm Air and/or Ventilation) OR proof of current City of Minneapolis Master's Card"; "a combined single limit of liability for bodily injury and property damage of $500,000; or $500,000 bodily injury and $200,000 property damage and thirty (30) day notice of cancellation"; "Current $25,000 Mechanical Bond (MB) on file at Minnesota Department of Labor and Industry"; "Proof of Worker's Compensation"; "$188.00 each"; "All Trade Licenses expire on December 1st"), stpaul.gov; Gas Burner (fuel gas burning equipment and systems), Oil Burner ("any oil-fired heating device"), Refrigeration ("central air conditioners, chillers, heat pumps, walk-in coolers, walk-in freezers, refrigerated cases") and Steam Fitting ("boilers, piping, pumps, coils, convectors, heat exchangers, radiation, in-floor heat") business trade licenses, same requirements (all last edited January 28, 2026), stpaul.gov; "Business Trade License, Competency Cards, and Trade Worker Registration" (last edited October 21, 2026: competency cards "$24.00 per trade", "expire on December 1"; "Every trade worker who works on any building or structure in Saint Paul must be currently registered"; $37 tier 1 (0-4 years), $70 tier 2 (5-6 years), $59 tier 3 (7+ years); registrations "expire after one (1) year"; warm air exams "held in January and July"), stpaul.gov; all read November 3, 2026.
10. City of Saint Paul, "Mechanical Permits & Inspections" and "Refrigeration Permit" ("Installation of any device using refrigerant for either comfort cooling or refrigeration of products (e.g., central air conditioners, chillers, heat pumps ...) requires a permit"), "Gas Burner / Oil Burner Permit" (a gas burner is "any natural gas fired heating device (e.g., furnace, boiler, space heater, or unit heater"), "Warm Air/Ventilation Permits & Inspections" (all last edited October 7, 2026), stpaul.gov; "Homeowner's Warm Air / Ventilation and Mechanical Permits Affidavit" ("It is unlawful for homeowners to perform Warm Air / Ventilation or Mechanical work on property that is rented, leased or occupied by others"; "The owner / permit holder must physically perform" the work), stpaul.gov (PDF); "Requirements for New Home Furnace Installations and Furnace Replacements" (2020 Minnesota Residential Energy Code R403.5.17: ACCA Manual S, "Oversizing of heating equipment shall not exceed 40 percent ... and oversizing of cooling equipment shall not exceed 15 percent"; "Furnace replacements require whole house heat loss calculations"), stpaul.gov (PDF); all read November 3, 2026.
11. City of Saint Paul, "Plumbing/Gasfitter Business Trade License" (covers "drainage, water, gas, and other piping systems"; "Both a $25,000 Plumbing Contractor Bond (PC) AND a $25,000 Mechanical Bond (MB) are now required to be filed with the Minnesota Department of Labor and Industry"; last edited January 28, 2026). stpaul.gov, read November 3, 2026.
12. City of Duluth, "Contractor Licensing" ("While there is no state license requirement for mechanical contractors, they are required to file a $25,000 mechanical contractor bond with MN DLI"), duluthmn.gov; "HVAC and Mechanical" ("The HVAC permit must be taken out on ePlace by a mechanical contractor bonded by the Minnesota Department of Labor and Industry (DLI)"; one- and two-family permits "can be taken out by the owner of the home or a mechanical contractor with a registered mechanical bond"; permits needed for furnaces, boilers, space heaters, gas fireplaces, ductwork, radiant, in-floor and baseboard heat, air-to-air exchangers, air conditioning and refrigeration equipment; commercial plan review "except for simple like-for-like equipment replacements (must be under 400,000 BTUs)"), duluthmn.gov; "Plumbing and Gas Piping" (gas piping permits "for new or replacement gas lines for items such as fireplaces, furnaces, or water heaters"; not needed "when replacing appliances and equipment that has an existing shutoff"; "The plumbing permit must be taken out by a plumbing contractor licensed by the Minnesota Department of Labor and Industry (DLI), except the owner of a single-family owner-occupied home"), duluthmn.gov; "Residential Projects" ("A handyman, or 'my neighbor's buddy,' is not legally able to pull a permit to perform work on behalf of a homeowner unless they are a licensed contractor"), duluthmn.gov; all read November 3, 2026.
13. City of Rochester, "Trade & Contractor Licenses" (HVAC contractor license under RCO 4-3, $125, covering "warm air heating, steam and liquid systems, hot water heating, chilled water cooling ... ventilation systems, refrigeration systems, gas burners and gas piping, oil burners and piping"; "Before a contractor can apply for an HVAC Contractor license, they must have at least one licensed master installer employed full-time"; master installer license $60, "issued to the individual applicant, and is not directly tied to the contractor"; certificate of competency, "$25 fee for each area of competency"; "All Trade and Contractor Licenses will expire on December 31"), rochestermn.gov; "Certificate of Competency Application, Master Installer" (areas: warm air heating and ventilation; hot water and low pressure steam heating; refrigeration and air cooling; gas piping; factory-built fireplaces, stoves and chimneys), rochestermn.gov (PDF); both read November 3, 2026.
14. City of Bloomington, "Contractor licensing and testing" (mechanical contractor bond on file at DOLI; "Minneapolis or St. Paul Certificate of Competency or proof of passing the City of Bloomington's mechanical test"; "Gas Installer - Class 'A' Gas lines to furnaces, boilers, make-up air and rooftop units"; HVAC, hot water/steam, oil burner, commercial refrigeration; test "$35"), bloomingtonmn.gov; City of St. Cloud, "Contractor Licensing & Mechanical Exam Information" (heating contractor license: "Hold a St Cloud Master A or B Mechanical Installer Certificate", "A copy of your Mechanical Contractor Bond Certificate", liability "$100,000 (for injuries to or death of one person)/$500,000 (on account of one accident)/$250,000 (for property damage) naming the City of St. Cloud as Certificate Holder"), ci.stcloud.mn.us; both read November 3, 2026.
15. Minnesota Statutes 326B.38 subd. 2 to 4 (installation of HVAC units "not covered by sections 326B.31 to 326B.399"; "The installation of electrical wiring to the unit is covered"; subd. 4: alteration, replacement or repair of HVAC equipment "and associated devices, controls, and wiring including wiring in or on the equipment" not covered "when the work is performed by an employee of a heating, ventilating, air conditioning, or refrigeration contractor provided that the employee performing the work has received a certificate of completion from a heating, ventilating, air conditioning, or refrigeration apprenticeship program approved by the state of Minnesota or any class of personal license issued by the commissioner"), revisor.mn.gov; 326B.33 subd. 21(d) ("Heating, ventilating, air conditioning, and refrigeration contractors and their employees are not required to hold or obtain a license ... when performing heating, ventilating, air conditioning, or refrigeration work as described in section 326B.38"), revisor.mn.gov; both read November 3, 2026.
16. DLI bulletin, "Clarification about electrical licensing requirements when replacing HVAC equipment and water heaters" (rev. 12/30/2024): an HVAC contractor may replace a furnace or air conditioner and "disconnect and reconnect the existing branch circuit connection without modifying the circuit" if "The work must be performed by an employee of an HVAC contractor" who "received a certificate of completion from an approved HVAC apprenticeship program in Minnesota" or "holds any class of personal license issued by the Minnesota Department of Labor and Industry (DLI)"; "*No DLI-approved HVAC apprenticeship program exists at this time"; "If the above conditions are not met, or if any modification to the existing branch circuit is needed, a licensed electrical contractor must be hired"; "A licensed electrical contractor must be hired to replace the electric water heater". dli.mn.gov (PDF), read November 3, 2026.
17. Minnesota Statutes 326B.31 subd. 29 ("Technology circuits or systems" means class 2, 3 or 4 circuits "for, but not limited to, remote control, signaling, control"), revisor.mn.gov; DLI, "Important Information about Technology Systems" ("Technology circuit and system work is required to be performed by IRS W2-type employees of companies licensed as technology system contractors or electrical contractors"), dli.mn.gov (PDF); DLI, "Individual Electrical Licensing or Registration Requirements and Inspection Requirements for the Installation of Technology Systems" (062025: "Class 2 or class 3 remote control circuits that control circuits or systems other than class 2 or class 3", residential dwelling: registration required, inspection required), dli.mn.gov (PDF); DLI, "Request for Electrical Permit, Contractor, Technology Systems" (rev. 6.20.2025, lists "Class 2 Remote Control (HVAC)"), dli.mn.gov (PDF); all read November 3, 2026.
18. DLI, Local Code Lookup, electrical authority by city (Minneapolis and Duluth: state; St. Paul, Rochester, Bloomington, St. Cloud: local), queried November 3, 2026 for our Minnesota electrical license guide. workplace.doli.state.mn.us.
19. Minnesota Rules 1346.0050 (adopts chapters 2 to 15 of the 2018 International Mechanical Code) and chapter 1346 as published (no A2L amendment; 1346.1104 repealed), revisor.mn.gov; DLI code book fact sheet, "2020 Minnesota Mechanical and Fuel Gas Code" (2018 IMC chapters 2 to 15, 2018 IFGC chapters 2 to 8, ASHRAE 62.2-2016; "effective April 6, 2020"), dli.mn.gov (PDF); DLI, "Rulemaking docket for Minnesota Rules Chapter 1346" (2024 IMC and IFGC; Request for Comments "published in the State Register on Feb. 2, 2026"; hearing, orders and effective date "To be determined"), dli.mn.gov; DLI, Mechanical and Fuel Gas Code TAG meeting notes, December 2, 2024 ("Section M1411.7 Group A2L refrigerant piping testing: The TAG consensus is to accept the 2024 IRC model code language"), dli.mn.gov (PDF); all read November 3, 2026.
20. U.S. EPA, "Section 608 Technician Certification Requirements" (technicians "who maintain, service, repair, or dispose of equipment that could release refrigerants into the atmosphere must be certified"; four types; "credentials do not expire"; "Apprentices are exempt from certification requirements provided they are closely and continually supervised by a certified technician"), epa.gov; "Questions and Answers about the Refrigerant Sales Restriction" ("Any person servicing, installing or disposing of stationary appliances (except the disposal of small appliances) must be a section 608 certified technician"; the seller verifies the buyer "is a certified technician, or ... employs a certified technician"), epa.gov; both read November 3, 2026.
21. U.S. EPA, "Phasedown of Hydrofluorocarbons: Reconsideration of Certain Regulatory Requirements Promulgated Under the Technology Transitions Provisions of the American Innovation and Manufacturing Act of 2020", 91 FR 31284, published May 26, 2026, effective July 27, 2026 (abstract: "allows the inventory of residential and light commercial air conditioning and heat pump equipment that was manufactured in the United States or imported into the United States before January 1, 2025, to continue to be installed"). federalregister.gov, read November 3, 2026.
22. U.S. EPA, "Lead Renovation, Repair and Painting Program" (Minnesota is not an authorized state; firm certification applies to "all firms, even sole proprietorships"), epa.gov; 40 CFR 745.83 (minor repair and maintenance: under 6 square feet per room inside, 20 square feet outside), law.cornell.edu; 40 CFR 19.4, Table 1 (TSCA penalty $49,772 per violation), law.cornell.edu; all read November 3, 2026 (from Deepsel's Minnesota license research).
23. Minnesota Rules 1300.0120, Permits: subp. 1 (an owner or authorized agent who intends to "erect, install, enlarge, alter, repair, remove, convert, or replace any gas, mechanical, electrical, plumbing system ... shall first make application to the building official and obtain the required permit"), subp. 4, items B and C (gas and mechanical work exempt from permit: portable appliances, "replacement of any part that does not alter approval of equipment or make the equipment unsafe", "steam, hot, or chilled water piping within any heating or cooling equipment", "self-contained refrigeration systems containing ten pounds (4.5 kg) or less of refrigerant or that are actuated by motors of one horsepower (0.75 kW) or less"). revisor.mn.gov, read November 3, 2026.
24. Minnesota Statutes 326B.121 subd. 1 ("The State Building Code is the standard that applies statewide") and subd. 2 (municipalities with an ordinance adopting the code as of January 1, 2008 "must continue to administer and enforce" it), revisor.mn.gov, read November 3, 2026; DLI, Local Code Lookup, "HAS ADOPTED THE BUILDING CODE" for 81 cities, queried November 3, 2026 for our Minnesota plumbing license guide, workplace.doli.state.mn.us.
25. Minnesota Statutes 326B.972 ("To operate a boiler, steam engine, or steam turbine an individual must have received a license"), revisor.mn.gov; 326B.988(a)(1) and (13) (the boiler law does not apply to "boilers and pressure vessels in buildings occupied solely for residence purposes with accommodations for not more than five families" or "hot water heating and other hot liquid boilers not exceeding a heat input of 750,000 BTU per hour"), revisor.mn.gov; DLI, "Boiler permits" (permit when input exceeds 100,000 BTU for steam, 200,000 BTU for hot water supply, 750,000 BTU for hot water heating; account linked to the mechanical bond; "Inspection fees are $80 per hour"), dli.mn.gov; all read November 3, 2026.
26. Minnesota Statutes 326B.91 subd. 4 ("High pressure piping" includes "any systems of piping hot water or other medium used for heating that exceed 30 p.s.i. gauge and 250 degrees Fahrenheit, or any system of high pressure steam, ammonia piping, or bioprocess piping"), revisor.mn.gov; 326B.92 subd. 1 ("No person shall construct or install high pressure piping systems without first filing an application for a permit"), revisor.mn.gov; DLI, "High pressure piping contractors" ("High pressure piping contractors must first employ an individual who has a master pipefitter license"), dli.mn.gov; all read November 3, 2026.
27. CenterPoint Energy, "New service connection" ("A houseline pressure test is required before we can set your new gas meter. You're responsible for contacting your local inspection authority, and they'll notify us when the inspection passes"), centerpointenergy.com; Xcel Energy, "Service Guide, Minnesota, North Dakota, South Dakota" (revised April 2022, gas section: Minnesota "All new natural gas meters may be locked at the time they are installed unless an approved inspection tag has been provided by the inspector"; "For all gas meters, only Xcel Energy may unlock or operate the inlet valve"; "authorized heating contractors or gas inspectors may operate the gas meter outlet valve (a), only after meeting the appropriate installation and inspection requirements"), xcelenergy.com (PDF); both read November 3, 2026.
28. Minnesota Statutes 326B.082 subd. 7 ("a monetary penalty of up to $10,000 for each violation of applicable law"), subd. 10 ("a civil penalty of $5,000 per day" for working in violation of a stop work order), subd. 16 ("a person who violates an applicable law is guilty of a misdemeanor"), revisor.mn.gov; 326B.081 subd. 3 ("Applicable law" includes "this chapter"), revisor.mn.gov; 609.02 subd. 3 and 609.03 (misdemeanor: "not more than 90 days or ... a fine of not more than $1,000"), revisor.mn.gov; all read November 3, 2026.
29. Minnesota Statutes 176.181 subd. 2 to 4 (every employer must insure; "a penalty of up to $1,000 per employee per week"; willful failure "is guilty of a gross misdemeanor"), revisor.mn.gov; DLI, Certificate of Compliance, Minnesota Workers' Compensation Law, dli.mn.gov (PDF); both read November 3, 2026 (from Deepsel's Minnesota plumbing license research).
30. Minnesota Secretary of State, "Business Filing and Certification Fee Schedule" (LLC articles of organization $155 online; certificate of assumed name $50 online), sos.mn.gov; Minnesota Department of Revenue, "Minnesota Tax ID Requirements" (a Minnesota Tax ID is needed to "Withhold Minnesota Income taxes from employees' wages"), revenue.state.mn.us; both read November 3, 2026 (from Deepsel's Minnesota electrical license research).
31. Minnesota Statutes 514.011 subd. 1 (contractors who will use subcontractors or material suppliers include the prescribed lien notice in the written contract; "A person who fails to provide the notice shall not have the lien"), revisor.mn.gov; 327A.02 subd. 3(b) ("home improvement work involving the installation of plumbing, electrical, heating or cooling systems": two years), revisor.mn.gov; both read November 3, 2026 (from Deepsel's Minnesota contract research).
32. Minnesota Statutes 178.036 subd. 5 (absent a collective bargaining agreement, "for occupations in the building and construction trades ... one apprentice for the first journeyworker employed at the work site plus one apprentice for each additional three journeyworkers employed at the work site", or the majority ratio in the trade, or an approved program ratio). revisor.mn.gov, read November 3, 2026 (from Deepsel's Minnesota plumbing license research).
33. r/ProHVACR post, August 24, 2024: "i run a 2man hvac startup company with a partner in the state of Illinois, which does not have a statewide license." reddit.com, quoted as checked in Deepsel's HVAC research, November 2, 2026.
34. Minnesota Statutes 326B.845 subd. 2: "An unlicensed person who knowingly violates sections 326B.802 to 326B.885 has no right to claim a lien under section 514.01 and the lien is void." Those sections are the residential building contractor licensing law. revisor.mn.gov, read November 3, 2026 (from Deepsel's Minnesota license research).
35. DLI, License and registration lookup (licenses, bonds, certifications and registrations issued by DLI). dli.mn.gov, read November 3, 2026.